Generally, existing brake rotors include solid, non-venting rotor designs and venting designs, as disclosed in U.S. Pat. No. 5,878,848 (vented). Accordingly, conventional ventilated brake rotors generally include a pair of mutually spaced-apart annular disks that present two opposed external braking surfaces for engaging brake pads under a clamping operation of a braking actuator (brake caliper). The space between the disks typically includes a number of vanes with flow passages defined between each pair of adjacent vanes that extend between the disks from their inner diameter to their outer diameter. Rotation of the rotor causes the vanes to induce air flow through the flow passages from the inner diameter to the outer diameter of the disks, providing increased convective heat transfer from the rotor. Inlets for the vanes reside adjacent the external braking surface of the base of the rotor.
Slots may be cut into one or more of the external braking surfaces of a brake rotor, as shown in U.S. Pat. No. 6,446,770, which allow for the collection of gases which are produced by the disc brake pad material when a braking force is applied to the external braking surfaces. Such slots may also be used as a cleaning mechanism to clean a corresponding brake pad surface to collect brake dust produced by the brake pads during braking. For additional cooling and/or venting of braking gases produced by braking, especially for today's high-performance automobiles and racing applications, a series of cross-drilled through-holes may be formed in each external braking surface, as shown in U.S. Design patent nos. D465,179 and D456,326.
The use of slots and cross-drilled holes however, decreases the heat dissipation surface area of a respective external braking surface as well as decrease the braking surface area. Either or both of these decreases in respective surface areas may result in a decrease in braking performance (e.g., increased braking distances). Moreover, the more rotor material removed (by the creations of slots and/or the use cross-drilled holes), the more prone the rotor may be to premature failure due to thermal fatigue. This may result in rotor warping.
Slotted rotors may also be prone to yet another problem. Collected brake dust may ultimately clog one or more slots after time resulting in a decrease or cessation of the ability of the slot to perform this job.